THE BOWEL is the site of absorption of vitamin K and its synthesis by micro-organisms. Pathological states in the alimentary canal may therefore be reflected in a lowered plasma prothrombin level. Hypoprothrombinemia of enteral origin is known to occur in severe protracted diarrhea1 and in several other conditions, all having in common an impairment of intestinal absorption.2
Interest in prothrombin in the pediatric literature has centered around hemorrhagic disease of the newborn. In older infants no marked difference in prothrombin activity from that in adults and older children has been noted. Rapoport and Dodd3 observed a prolongation of prothrombin time in seven infants with chronic diarrhea and drew attention to the apparently not infrequent occurrence of hypoprothrombinemia in infants suffering from this condition.
Animal experiments4 and experience with human beings5 have shown that hypoprothrombinemia may result from the use of sulfaguanidine, succinylsulfathiazole and orally administered